1. Field of the Invention
The present invention pertains to single phase stepper motors and, more particularly, to such motors for driving clocks.
2. Discussion of the Prior Art
Single phase stepper motors formed of a bipolar permenent magnet rotor and a stator of a non-magnetic material having a field winding arranged parallel to the rotor shaft are known in the prior art. The stator of such prior art motors is surrounded by a ring of ferromagnetic material which is provided with two apertures constituting auxiliary poles. Although such single phase stepper motors were developed in an attempt to minimize current consumption, such motors suffer from the disadvantage of requiring too much power if a torque of the order of hundreds of millipound-centimeters is to be produced, such as is required for the second-hand shaft of a clock.